Re^3: SSH2 - Asynchronous Opens & Synchronous Commands

[salva]

in reply to Re^2: SSH2 - Asynchronous Opens & Synchronous Commands
in thread SSH2 - Asynchronous Opens & Synchronous Commands

You can run shells with Net::OpenSSH quite easily and even use Expect to interact with them:

my %ssh;
for my $host (@hosts) {
  $ssh{$host} = Net::OpenSSH->new($host, async => 1, ...);
}

for my $host (@hosts) {
  my $ssh = $ssh{$host};
  my ($pty, $pid) = $ssh->open2pty; # whith out command launchs a shel
+l
  my $expect = Expect->init($pty);
  $expect->...

}

[5haun]

This is an interesting proposal. I'll have to do some tests with this. Thanks. I'll report back with my findings.

Update: I'm still working on this test case. I've got something implemented using Telnet, but I need to do some more testing. I'll post code tomorrow morning.

In the meantime, how would you handle waiting for all the async open requests to complete? I this what wait_for_master is for? My current solution loops checking for $ssh->wait_for_master(1) returning true.

Thanks.

[salva]

You have to call $ssh->wait_for_master(1) repeatedly until it succeeds:

my %connecting = map { $_ => 1 } @hosts;
while (1) {
  for my $host (keys %connecting) {
    my $ssh = $ssh{$host};
    if ($ssh->wait_for_master(1)) {
      delete $connecting{$host};
    }
    elsif ($ssh->error) {
      # handle connection error
      delete $connecting{$host};
    }
  }
  last unless %connecting; 
  select (undef, undef, undef, 0.05);
}

[5haun]

@Salva

Thank you. So far, it looks like OpenSSH+Telnet will do what we need it to, although I am having to make some adjustments for the use of Telnet.

BTW, it would be nice (i.e. enhancement request) if $ssh->error provided a message that could differentiate between password, connect, and timeout failures: I get "unable to establish master SSH connection: bad password or master process exited unexpectedly" for authentication, for connect (socket not open), and for timeout errors. I need to be able to differentiate (that was pretty easy to do with Net::SSH2). Unless you have a better test, it looks like I'll need to try a socket connect before the opens to differentiate.